Can someone help me with my zipper?

The zipper broke on my favorite pair of pants. The metal tab thingy came off. Now it won’t stay locked in the up position and keeps sliding down and unzipping. Not a good look for running to the grocery store. Is there any way to fix this without replacing the whole zipper? These are just everyday work pants, not worth replacing the zipper or spending any money on. I got them at Goodwill. My problem with just throwing them in the recycle bin is that they are my most comfy broken in pair of everyday get my work done pants.
Any suggestions?